1. Field of the Invention
The present invention relates to an image forming apparatus and control method thereof. Particularly, the present invention relates a technique regarding notification of a trouble state in the image forming apparatus.
2. Description of the Related Art
In general, when an image forming apparatus such as a printer detects a trouble in it, it displays an error code specifying the trouble location on the operation unit, and notifies the user of the trouble. The image forming apparatus prompts the user to report the gist of the notification to a serviceman, thereby solving the trouble.
However, even if an error occurs owing to an electrical event, the apparatus itself is not actually damaged in most cases. Examples of the electrical event are a communication failure arising from sudden electrical noise generated by static electricity, a sensor input signal detection error, and a malfunction caused by an unstable electrical element operation which may temporarily occur owing to insufficient voltage application upon instantaneous voltage drop. Also, a driving failure sometimes arises from an externally generated excessive load applied to the internal driving source of the apparatus due to an unexpected operation error in the use of the apparatus by the user.
In most cases, the apparatus can originally recover from such an abnormal condition to a normal condition without calling a serviceman. However, the apparatus notifies the user of trouble information on the operation unit, so the user reports the trouble information to the serviceman. This may arouse a fear of generating a period during which the user cannot use the apparatus, and a fear of causing unnecessary work by a serviceman.
To solve this problem, there is disclosed a technique of determining the occurrence of an abnormal condition for which a serviceman need not be called. For example, in Japanese Patent Laid-Open No. 2011-131536, a control unit configured to detect a trouble stores, for each trouble type, information representing whether or not a trouble has been detected. After detecting a trouble, if the control unit detects the same trouble within a predetermined period, it notifies the user of information about the trouble. If the control unit does not detect the same trouble within the predetermined period, it cancels information representing that the trouble which occurred previously has been detected, thereby changing the information to information representing that no trouble has been detected.
In Japanese Patent Laid-Open No. 2011-131536, when the same trouble has not occurred within a predetermined time after the trouble occurred previously, stored information representing that the trouble has been detected is canceled. However, considering this control applied to actual use by a user, even in a situation in which a component in the apparatus is being damaged, the trouble detection information is canceled upon the lapse of the predetermined time. As a result, the user may not be notified of the trouble information.
For example, a case in which the user prints out a specific set of image information data from the image forming apparatus (to be referred to as a job hereinafter) will be explained. The number of sheets printed out from the image forming apparatus varies for each user of the image forming apparatus. Assume that the printout sheet count is excessively small for a given user. Also, assume that when this user uses the image forming apparatus, there is a target component whose trouble would be usually detected during execution of a job, part of this component is actually being damaged, and the component operates unstably.
For example, assume that one wire out of a bundle of electrical wires is being disconnected and a contact failure has occurred. In this case, the apparatus may operate normally or abnormally. If the operation is determined to be normal without detecting the trouble of this component immediately after the trouble is detected once after the start of executing the job, information about the trouble of the component changes from a trouble detection state to a no-trouble detection state upon the lapse of time from the timing when the trouble was detected once. When another user uses the apparatus again, the trouble is detected once again during execution of a job, the apparatus stops, and then the apparatus returns again to a normal operation. Such an unstable operation repetitively occurs. As a result, the user may not be notified of reliable trouble information.
Trouble detection is similarly performed during a period other than during execution of a job. When a trouble detection target component in the apparatus is being damaged and operates unstably, if information about detection of a trouble changes to a no-detection state upon the lapse of time in a case in which, for example, the apparatus stands still for a long period, the user may not be notified of trouble information upon detection of the trouble. This also applies to a case in which, during execution of a function which is rarely used, a trouble of an apparatus component regarding execution of this function is detected.
Since trouble information is rarely notified, the apparatus remains used in an unstable state to the end of time. If the user keeps using the apparatus in this state, a damaged component may affect a normal component. This makes it difficult to specify the original cause of the trouble.